Method for fabricating a beryllium fiber reinforced composite having a titanium matrix

ABSTRACT

A process for forming fibrous beryllium/titanium composites from separate beryllium and titanium materials wherein the resultant composite consists of continuous Be fibers of selective size, array, placement, and geometry in a matrix of continuous Ti or Ti alloy phase. The process is characterized by surrounding discrete preformed Be shapes or fiber precursor bodies with either powdered or preformed Ti material and extruding a cannister containing this assembled body at a temperature of from 1,350* to 1,525*F. to a reduction ratio of from 6/1 to 100/1 or greater to form a consolidated Be/Ti composite having a very limited but discernible intermetallic reaction zone of titanium beryllide formed in situ. After extrusion and cooling, the yield strength of the composite can, if desired, be substantially improved by cold working at 70% to 80% of the ultimate tensile strength. Composite beryllium titanium bodies so fabricated have tensile properties superior to those of Be/Ti composites fabricated up to 1,300*F. and superior ductility, toughness and strength to those of Be/Ti composites made from blended Be and Ti powders hot extruded at 1,350*F. to 1,525*F. Furthermore, because of the capability of controlling the geometry of the array of fibers in composite sections, it is possible to &#39;&#39;&#39;&#39;design&#39;&#39;&#39;&#39; properties to specific applications. These materials may be fabricated by known techniques into aircraft engine parts, e.g., gas turbine compressor blades, vanes and shafts. They would also be useful in other shaft applications requiring high modulus and low weight such as high speed machinery.

Unite States atent [191 Goodwin METHOD FOR F ABRICATING A BERYLLIUMFIBER REINFORCED COMPOSITE HAVING A TITANIUM MATRIX [75] Inventor:Vernon L. Goodwin, Willowick,

Ohio

[73] Assignee: Brush Wellman Inc., Cleveland,

Ohio

[22] Filed: Aug. 18, 1972 [21] Appl. No.: 281,620

[52] U.S. Cl 29/419, 29/182.2, 29/420.5, 29/D1G. 45, 29/DIG. 47, 75/226[51] Int. Cl B221 3/24, B23p 17/00 [58] Field of Search. 29/DIG. 31,DIG. 45, DIG. 47, 29/419, 420, 420.5, 182.2; 75/200, 226

Primary ExaminerCharles W. Lanham Assistant Examiner-D. C. Reiley, III

Attorney, Agent, or Firm-McNenny, Farrington, Pearne & Gordon [11]3,821,841 1 July 2,1974

[5 7] ABSTRACT A process for forming fibrous beryllium/titaniumcomposites from separate beryllium and titanium materials wherein theresultant composite consists of continuous Be fibers of selective size,array, placement, and geometry in a matrix of continuous Ti or Ti alloyphase. The process is characterized by surrounding discrete preformed Beshapes or fiber precursor bodies with either powdered or preformed Timaterial and extruding a cannister containing this assembled body at atemperature of from 1,350 to 1,525F. to a reduction ratio of from 6/1 to100/ 1 or greater to form a consolidated Be/Ti composite having a verylimited but discernible intermetallic reaction zone of titaniumberyllide formed in situ. After extrusion and cooling, the yieldstrength of the composite can, if desired, be substantially improved bycold working at 70% to 80% of the ultimate tensile strength. Compositeberyllium titanium bodies so fabricated have tensile properties superiorto those of Be/Ti composites fabricated up to 1,300F. and superiorductility, toughness and strength to those of Be/Ti composites made fromblended Be and Ti powders hot extruded at 1,350F. to 1,525F.Furthermore, because of the capability of controlling the geometry ofthe array of fibers in composite sections, it is possible to designproperties to specific applications. These materialsmay be fabricated byknown techniques into aircraft engine parts, e.g., gas turbinecompressor blades, vanes and shafts. They would also be useful in othershaft applications requiring high modulus and low weight such as highspeed machinery.

20 Claims, 5 Drawing Figures 1 METHOD FOR FABRICATING A BERYLLIUM FIBERREINFORCED COMPOSITE HAVING A TITANIUM MATRIX ART Beryllium metal hasthe advantage of possessing one of the higher specific elastic moduli(elastic modulus/- density) of any existing metal. However, opposingdisadvantages are the low fracture toughness and high fabricating costs.Thus, the use of beryllium as a structural metal has been limited.Titanium and its alloys in contrast have good specific strength(strength/density) and acceptable fracture toughness properties, but alower than desired elastic modulus. Alloys containing substantialamounts of Be and Ti prepared by conventional melting practices cannotavoid the formation of excessive amounts of brittle intermetallicreaction products which cause the overall alloy to be uselessly brittle.

By this invention, Be and titanium materials can be bonded together andmutually reinforced by permitting a limited interaction betweencontacting areas of adjacent Be-Ti material to form an amount oftitanium beryllide sufficient to join strongly together, butinsufficient to interfere with the desirable individually contributedproperties of the Be and Ti and render the product brittle. Fabricationof Be/Ti composites has already been investigated and reported byAbkowitz in US. Pat. No. 3,475,142. Schmidt in US. Pat. No. 3,609,855describes a method of hot rolling assemblies of Be/Ti into compositeribbon. Abkowitz limited the temperature of processing treatment to1,300F. and below in order to ensure against the formation of titaniumberyllide interaction products between beryllium and titanium particles.Such intermetallic structures are recognized as being brittle andcausing nonductile bonds leading to premature failure under stressing.The

for aircraft structural elements. Also, a family of applications existwherein Be/T i fibrous composites can be produced as shafting and usedto replace steel and other commonly used shaft materials which arerelatively heavy compared to Be/Ti composites. The advantage of a lowdensity material with a modulus of elasticity comparable to steel isthat the resonant frequency of the shaft is increased, thereby allowingthe shaft to operate at higher speeds than steel shafts before excessivevibration is encountered. The relationship of material resonantfrequency (f,,) with elastic modulus (E) and material density (p) is asfollows:

fn V lp By this relation, a Be/Ti composite with an E 29 X 10 psi and p0.10 lbs./cu.in. would have a 75% higher natural resonant frequency thansteel, all other things being equal. The Be/T i composite can thussafely operate at approximately 75% higher speeds and have the furtheradvantage of weighing about one-third less than that of an equally sizedshaft of steel.

Further possibilities in a fibrous Be/Ti composite fabricated by thisinvented process would be the customized array of Be fibers in the crosssection. For instance: if a composite beam were to be desired which wassubjected to bending in use, then a high population of continuous Befibers could be placed in the outer area of the cross section so as toincrease theelastic modulus selectively. Thus, the beam could verybeneficially be stiffened by selective fiber placement in areas ofmaximum bending strain by selective concentrated use of Be fibers there.In less critical areas where bendpresent work has found in processingfrom l,375F.

and higher that fibrous composite bodies were formed exhibiting greatertensile ductility than those fabricated at 1,300F. and below. Also,higher strength resulted in processing composite beryllium/titaniummaterial in the range of 1,375 to l,525F. This is contrary to the arttaught by Abkowitz and to that generally recognized presently bymaterial scientists. Metallographic examination at 500 10,000X ofberyllium/titanium composities made by processing powder blends froml,l00 1,525F. showed no evidence of significant interparticle titaniumberyllide reaction at l,300F. and below, but did find evidence of someat l,375F. and above, the reaction zone being thicker with highertemperatures and longer times of exposure at these temperatures.

The present work departs from that of Schmidt in that he usesexclusively the process of hot rolling and is concerned with fabricatingcomposite ribbon only.

One purpose of the present invention is to provide a beryllium/titaniumcomposite material having a modulus of elasticity substantially greaterthan that of titanium (16 X 10 psi), a density similar to or slightlygreater than that of aluminum (0.100 to 0.135 lb. per cubic inch), atensile ductility in the longitudinal direction of 2% or greatercombined with a transverse direction elongation of 1.0% or greater, anda notched Charpy impact strength of 5 foot pounds or greater at roomtemperature. These characteristics are considered by aircraftmanufacturers to be worthy properties ing strains were low less volumeper cent of Be and more of Ti material could be employed to improve theductility, toughness, impact strength and tensile strength in this areaas well as lower overall cost. As a result of the opportunity todistribute location, size and proportion of continuous Be fibers and theproportion of continuous Ti material matrix, great flexibility inproduct property distribution exists and fibrous Be/Ti composite-shapescan be customized in structure and properties so as to achieve maximumdesign goals, including stiffness, weight, strength, ductility, andtoughness. 1

The present process eliminates many of the steps taught by the priorart, enables the utilization of commercial beryllium and commercialtitanium materials without sacrificing raw material and processingsavings. The present process further enables the use of higher hotworking temperatures at which extrusion can be effected more readilyallowing greater reductions, lower loads on tooling or fabrication ofmore complex shapes. Finally, the present process produces fibrouscomposite material of mechanical properties and ductility especially inthe direction transverse to working higher than attained by apowder-powder composite process. The fibers of beryllium are continuous,that is, they extend in an axial direction, and preferably fromend-toend of the extruded member. As used herein the term fiberprecursor body is intended to identify the form the beryllium componenttakes prior to extrusion after which it assumes a more nearly fibrousform than being of relatively small cross-sectional area, but very muchelongated as well as fully densified due to the extrusion. The fiberprecursors may be shaped as rods, bars, wires, etc. of varying degreesof density ranging from loose powder to fully densified beryllium.

The density and modulus of elasticity requirements above set forth aresatisfied by beryllium/titanium composite containing from 40 to 60volume percent beryllium, balance titanium or titanium alloy. Thepresent invention, however, is also applicable to fibrous composites ofberyllium and titanium outside of the 40 to 60% by volume beryllium forwhich uses may be contemplated in aircraft structures and elsewhere.

BRIEF STATEMENT OF THE INVENTION Briefly stated, the present inventionis in a process for producing and a product produced by forming anextrudable beryllium/titanium assembly of discrete beryllium fiberprecusor bodies extending from end-to-end of said assembly; filling thebalance of the assembly with titanium or titanium alloy to form acontinuous matrix surrounding said bodies; encasing the assembly in anextrusion cannister and extruding the cannister at a temperature of froml,350 to l,525F at a reduction ratio of from 6:1 to 100:1 or greater toform a solid fibrous beryllium/titanium composite.

In a more detailed embodiment in accordance with the present inventionthe following steps are included.

1. Designing the array configuration of Be fibers to be achieved in thefinal solid extruded Be/Ti composite shape.

2. Relating this configuration back to the necessary extrusion billetarray configuration.

3. Assembly of an extrusion billet inside a steel cannister ofone-sixteenth inch to one-half inch thick wall having the desired arrayconfiguration. This in terms of input material may consist of thefollowing:

a. Be preforms Ti powder In this instance, Be preform fiber precursorbodies made from wrought Be or some form of rigidized or consolidatedpowders are maintained in a desired array by mechanical means oradhesive fixturing. The Be preforms are then surrounded by a material ofTi powder poured in around the preforms and the powder vibrated ortamped to as high a density as possible. Additional powder may be placedin the ends of the extrusion billet to supply additional volume of thelow density powder which will flow in place during hot extrusion. (SeeFIG. 2.)

b. Solid Ti Be powder or preforms Alternatively the Ti materialcomponent may be a solid cast or wrought body processed commerciallyinto which holes have been machined or otherwise prepared to receive theBe component. These holes can be filled with Be powder as the fiberprecursor body which can be at least partially consolidated byvibration, tamping or cold pressing.

c. Be powderTi powder Another alternative is that both the titanium andberyllium be in powder form. In this instance a thin separator such asplastic tubing or paper of the proper diameter is held in the desiredway by mechanical means. Ti powder is poured around the thin wallplastic tubing and Be powder is placed inside the thin wall plastictubing. The assembly is then vibrated or tamped to as high a density aspossible. The thin-wall separator is then mechanically removed.

Aluminum or Ti or Ti alloy thin-walled tubing can also be used asseparators. In this instance, the separators may remain in place andalloy with either the Ti or Be during subsequent processing.

4. The canned extrusion billet assembly having the desired array of Beand a Ti matrix may then be outgassed at 600 to 1,300F. in the presenceof a suitable vacuum of approximately 0.1 micron of Hg absolute pressure(optional).

5. The extrusion billet assembly may be cold pressed or isopressed at5,000 60,000 psi before extrusion. lsostatic pressing may so distort thecan as to necessitate the removal of the compacted body, machining todesired size and recanning (optional).

6. The canned or re-canned billet is heated uniformly up to the desiredextrusion temperature of l,350 to 1,525F. and held for a minimal timeperiod.

7. The heated billet is then extruded to at least a 6/1 reduction ratioand up to approximately 50/1 reduction ratio using commercial hotextrusion techniques.

8. The extruded solid Be/Ti composite is cooled to room temperature andstripped from its steel jacket by mechanical means or pickling in nitricacid.

9. When extrusion reduction ratios upwards of 20/1 are desired, it maybe found convenient to re-extrude the jacketed billets at the sameelevated temperature above 1,375F using portions of clad extruded rod orshape. Alternatively, the cladding may be stripped, and theberyllium/titanium composite re-jacketed for further reduction incross-sectional area. In this latter case, bundles of previouslyextruded and dejacketed composite rod or shapes may be both furtherreduced in cross section and metallurgically bonded together in thissecondary extrusion operation.

10. Resultant extruded beryllium/titanium composite material aftercooling to room temperature may be cold worked at to of ultimate tensilestrength in order to remove normal residual tensile stresses present inthe beryllium phase due to incompatibilities in contraction and modulusof elasticity and to impose a new residual compressive stress on theberyllium phase. With such prestressing, the material then elasticallydeforms in tension according to its true modulus of elasticity which isin the range of from 26 to 32 X 10 pounds per square inch up to highstress levels. The 0.2% offset yield strength, an important engineeringdesign parameter, has then been substantially raised.

It is here again pointed out that the processing temperatures of thepresent invention are generally higher than those previously used forthe reason that hot working processes such as extrusion are facilitated.By this is meant that pressures required to extrude decrease with highertemperature, and greater reduction of cross section can be effected forequivalent pressures at 1,350 1,525F as compared to 900 1 ,300F used inprior art. For equal reduction ratios lower pressures are required,resulting in longer tool life. It has been found that beryllium/titaniumcomposites hot extruded at l,350 1,525F exhibit a tensile strengthcomparable to or greater than those extruded at lower temperatures, butgreater ductility than those extruded at 1,300F and below. A titaniumberyllide structure has been metallographically identified betweencontacting beryllium and titanium particles when the compositie isextruded at 1,350F and higher. Development of this phase may result in astronger bond providing greater strength and ductility. Materialextruded at 1,525F and above exhibits lower strength and ductilityperhaps because the interparticle titanium beryllide structure has grownexcessively thick.

It becomes convenient to illustrate the process and resulting productsproduced in accordance with the present invention by specific examples,and in this connection reference may be had to the drawings whichillustrate specific arrays of beryllium fiber precursor bodies intitanium matrices, and specific cannistered assemblies, and wherein:

FIG. 1 is a diagrammatic and schematic crosssectional view of an arrayof beryllium rods of two different diameters arranged on and supportedon a mild steel disc. The interstices will be filled with titanium alloypowder to form the extrusion assembly.

FIG. 2 is a diagrammatic and schematic crosssectional view of a canisterprior to extrusion.

FIG. 3 shows diagrammatically and schmatically an array useful in makinga hollow fibrous beryllium reinforced titanium composite shaft.

FIG. 4 shows diagrammatically and schematically a cross-sectional viewof a cannister for a hollow shaft prior to extrusion.

FIG. 5 shows diagrammatically and schematically a cross-sectional viewof an extrusion assembly of beryllium bars in a titanium matrix, thebars being arranged in a star pattern.

DETAILED EXAMPLES OF INVENTION The present process contemplates the useof commercially produced and readily available beryllium and titaniummaterials including powders, solid shapes and alloys. This is incontradistinction to specially produced powders such as themicroquenched, age-formed, shot" powders of the prior art.

The beryllium used in accordance with this work is commerciallyavailable and comes from a vacuum-cast metal source. Beryllium powder iscomminuted by chipping vacuum-cast billets and grinding by knownprocedures. Solid beryllium preform shapes useful as fiber precursorsare fabricated from powders, preferably containing from 0.2% to 6% byweight BeO, usually by the widely used commercial process of vacuum hotprocessing, and resultant dense bodies are then machined into desired Bepreform shapes. Alternatively, preform shapes from beryllium powder canbe fabricated by either cold pressing alone, or by cold pressing andsintering in vacuum at l,l50 1,250C or by cold pressing, sintering andcoining at from room temperature up to 1,200F. (and optionallyresintering). Finally preform shapes from beryllium powder can be madeby mixing with common binders to achieve porous but handleable fiberprecursor bodies. Preform shapes can also be obtained from commerciallyavailable wrought forms of Be including extrusions, sheet metal orforgings. It is such preform shapes, e.g. rods, bars, wire, etc., whichare preferably used as beryllium fiber precursors in fabricating thecomposites of the present invention.

The titanium material used in this process consists of both powders andsolid material. Titanium materials may consist of up to 100% Ti or acommercially available powdered titanium alloy. These powders may beproduced commercially by the conventional hydridedehydride process whichis well known, or by other commercial processes. Generally, thesepowders have a particle size in, or particle size distribution over, therange of from mesh to +325 mesh, and preferably no more than 3 X 10inch. The solid Ti material also used in the present process can be upto Ti or of commercial Ti alloy composition. Such solid Ti material iscommercially available in a vacuum are cast and wrought form in a widevariety of shapes and sizes adaptable to use in this process.

Example No. 1 (50 Be/50 Ti by volume Fibrous Composite) 1. MaterialInput Be-Vacuum hot pressed Be powders of full density extruded andmachined into inch dia. (10 each) and inch dia.(6l each) rods.

Ti-6AI-4V alloy powder of hydride derivation and of 50 +325 mesh size.

2. Array Configuration in Extrusion Billet. See FIG. 1. There is hereshown a plurality of beryllium rods held in a drilled circular mildsteel disc 0.5 inch thick and 4.480 inches in diameter, the largerdiameter rods being arranged at the apices of equilateral triangles. Thefree space is ultimately filled with the titanium alloy powder. 1

3. Extrusion Billet Assembly.

A. With reference to FIG. 2, there is showndiagram matically anextrusion canister. The canister is composed of a plug 10 havingintegral therewith a drilled plate 12 into which the prefabricatedberyllium rods 14 are inserted as indicated in FIG. 1. Welded to theplug 10 is a steel tubular body 16 having a wall thickness ofapproximately 0.25 inch and, in the specific example involved, being 5inches in outside diameter. This is made of mild steel. As indicated,the titanium alloy powder fills the spaces between the beryllium rods 14and, because of its powder condition, extends beyond the extremities ofthe beryllium rods. The canister is sealed with a plug 18 drilled toprovide an exit bore 20 and having a stainless steel evacuation tube 22welded thereto. The evacuation tube is to enable removal of gases fromthe interior of the canister after which it is sealed.

4. Extrusion Cannister outgassing Evacuated to 0.1 micron of Hg.

5. Extrusion temperature 1,425F

6. Extrusion ratio 15.7 (5 inches dia. to 1.25 inches dia.)

7. Extruded properties Example No. 2 (50% Be/50% Ti by volume) FibrousComposite 1. Material Input Be-Vacuum hot pressed to powder of fulldensity. extruded and machined into )4 inch dia. rods.

Ti Ti 6A1 4V alloy powder of hydride deviation and of 50 +325 mesh size.

2. Array configuration in extrusion billet similar to FIG. 1, but billetsize 1% inches dia.

3. Extrusion billet assembly Similar to FIG. 2, but billet 1 /4 inchesdia.

4. Extrusion cannister outgassing none.

5. Extrusion temperature 1,375F.

6. Extrusion ratio 20/1 (to 0.39 inch dia. composite).

Example No. 3 (50 Be/SO Ti by volume fibrous composite) 1. CommentExample No. 3 is the re-extruded product of Example No. l.

2. Extrusion billet 1% inches dia. composite of Example l jacketed in a1% inch OD X 1% inches ID steel tube.

3. Extrusion temperature 1,450F.

4. Extrusion Ratio 20/1 (composite 1 /4 inches dia. to 0.28 inch dia.).

5. Extruded properties.

Property As Extruded Prestressed to I ksi (tension) Long. Transv. Long.

Tensile Fr ksi 143 90 148 3 Pt. Bend Example No. 4

(50% Be/50 to Ti by volume Fibrous Composite) 1. Material InputBe-Vacuum hot pressed Be powder to full density extruded and machinedinto 0.445 inch dia. X 14 inches long rods (24 each). Ti 6A1 4V alloypowder of hydride deviation and of 50 +325 mesh size.

2. Array configuration in extrusion billet. See FIG. 3.

B. In this example, the arrangement of the beryllium rods is shown inFIG. 3. Thus, beryllium rods 24 are mounted in a base 26 formed of mildsteel in a circular pattern. In the specific example, the outside radiusof the plug portion 26 is 2.25 inch, the inner radius is 1.625 inches,and the centers of the beryllium rods 24 are disposed on a radius of1.937 inch.

3. Extrusion billet assembly C. With reference to FIG. 4, there isprovided a nose plug 26 which carries the beryllium rods 24 as indicatedin FIG. 3. The canister generally indicated at 28 is provided with atubular body 30 and carries a center core 32. The interstices betweenthe beryllium rods and the center core 32 are filled with titanium alloypowder 34 as above indicated. A tail plug 36 encloses the canister andincludes a tubular member 38 extending therethrough for evacuating thesystem and ultimate sealing. The extrusion canister of FIG. 4 isapproximately 22.5 inches long and the elements are formed except Whereindicated of hot rolled steel. The canister is 5 inches in diameter andthe walls 025 inch thick.

4. Extrusion Cannister outgassing 5. Extrusion temperature 6. Extrusionratio 7. Extruded properties Prestressed to Property As Extruded I00 ksi(tension) Long. Transv. Long.

3 Pt. Bend Test Ult. strength F1, ksi 260 27] Yield strength ksi Elong.71 4.6 4.2

EXAMPLE NO. 5

As Extruded u 153 ksi 66 ksi 3 7:

EXAMPLE NO. 6

Be powder of 50 +l00 mesh was cold pressed at 10,000 psi into 0.30 X0.22 inch cross-section retangular bars. These bars were assembled intoa can and surrounded by Ti-6Al-4V powder as shown in the FIG. 5:

D. With reference to FIG. 5, there is shown diagrammatically andschematically another arrangement for beryllium bars 40 having thespaces therebetween filled with titanium powder 42. In general, thestructure of the canister is essentially the same as shown in FIGS. 2and 4.

The can was outgassed and extruded at 1,450F. 20:1

resultant properties:

As Extruded 1 159 ksi F, 60 ksi e, 4.7

The impact resistance of Be/Ti fibrous composites is markedly superiorto monolithic Be when both are measured by the well known Charpy test.The exact extent to which these composites resist impact (measured asstandard Charpy V-notch) is dependent on the final size of the fibers inthe composite. For instance, in Example 1 the fiber size was coarse andCharpy was 5.9 foot-pounds. The re-extruded product of Example 1 inwhich the fibers were of 1/10 of Example 1 was also tested. The Charpyimpact in this case increased to 8.8 foot-pounds.

The method of achieving the fiber precursor has been found to havelittle bearing on impact performance. This is evidenced by impactperformance similarities between Examples 1 and 5 for similar sizefibers.

alloy powders of hydride derivation. 20 mesh particle size or smallerand fractions thereof. Primary densification data is listed below Arrayconfiguration varied Extrusion billet assembly varied Extrusioncannister outgassing varied Extrusion ratio 6:1 to 50:1 Extrusiontemperature 1,350 1,525F Properties For given metal compositions underuniform conditions of extrusion, it has been found that the type of Bematerial and Ti material or its form used had little significance inrespect to the longitudinal properties measured in the direction ofextrusion of the extruded fibrous composite product. That is to say,whether dense Combinations of Be and Ti Material Forms Used to AssemblyExtrusion Billet for Composites Ti & Ti Ti & Ti Alloy Alloy PowderPowder Vibrated Cold 7 Solid or Pressed Ti & Ti

Tamped (lnc. lsostat.) Alloy Vibrated or tamped Be powder X X XPressureless sintered Be powder X X X Cold pressed (including isostatic)Be powder X X X Cold pressed (including isostatic) and sintered Bepowder Vacuum hot pressed (VHP) Be Wrought VHP Be Material andprocessing information relative to making extrusion billets havingdesired arrays of Be shapes in a Ti matrix are listed below:

1. Materials a. Be powder commercial attritioned powder of -20 meshparticle size or smaller and screened or classified fractions thereof.In general, the particle size range is desirably controlled to be withina relatively narrow particle size distribution in a given sample, e.g.all under 50 mesh.

b. Ti powder commercial Ti and Ti 6A1 4V, Ti

- 5A1 2.5Sn, Ti 6A1 2Sn, and other titanium extruded VHP Be rod,machined rod, or some form of porous compacted powder was used to forman array in the Ti matrix, the resultant extruded fibrous composite hadsimilar longitudinal mechanical properties provided the final compositehad an identical array and full densification of the beryllium as wellas the titanium was accomplished.

Properties achieved rather than being dependent upon initial materialform and density were related significantly to the temperature ofextrusion, the extrusion ratio and the chemical (Beo content) and/orphysical (particle size) composition of the Be and Ti materials.

Bearing this in mind, the following properties were achieved by extrudedcomposites of 50 60% by volume Be fibers in a Ti material matrix:

Low End of Range Properties Properties Conditions (LongitudinalDirection) Fr (prestrcssed) 60-80 ksi Low extr. temp. I400F Low extr.ratio l2:l F, 90 llS ksi e, -30% Be powder low in oxide,

2% Beo F 250 300 ksi e,, l 6 High End of Range of Properties High extr.temp. 1400-1525F (prestressed) 80l00 psi High Extr. ratio l2:l ll5 140psi Be powder high in oxide 2 5% Bee F, 300 ksi sectionally equi-axed,the F, (transverse) was approximately 302000 to 30,000 gamers the ratiotfwidth to thickness increased to 8 or greater, the transverse F,increased to 100,000 psi. Q What is claimed is l. A process for forminga solid fibrous composite from beryllium and titanium in which thetitanium material forms a continuous matrix surrounding elongatedberyllium fibers which comprises the steps of:

a. forming an extrudable beryllium/titanium assembly of: l. discreteelongated beryllium fiber precursor bodies extending axially of saidassembly; 2. filling the balance of the assembly with. titanium to forma continuous titanium matrix surrounding said bodies; 1 b. encasing saidassembly in an extrusion canister;

and c. extruding said canister at a temperature of from 1,400 to l,525F.at a reduction ratio of from 6:1 to lO0:l to form a solid fibrousberyllium/titanium composite. 2. A process in accordance with claim 1which also includes the step of prestressing the extruded composrte.

3. A process in accordance with claim 1 in which the beryllium fiberprecursor is formed from beryllium powder having a particle size nogreater than 3 X 10 inch.

4. A process in accordance with claim 1 in which the beryllium has aberyllium oxide content of from 0.2% to 6% by weight.

5. A process in accordance with claim 1 in which the beryllium fiberprecursors are composed of vacuum hot pressed beryllium.

6. A process in accordance with claim 1 in which the beryllium fiberprecursors are composed of cold pressed beryllium powder.-

7. A process in accordance with claim 1 in which the beryllium fiberprecursors are composed of cold pressed and sintered beryllium powder.

8. A process in accordance with claim 1 in which the beryllium fiberprecursors are composed of cold pressed, sintered and coined berylliumpowder.

9. A process in accordance with claim 1 in which the beryllium fiberprecursors are composed of beryllium powder rigidized with a binder.

10. A process in accordance with claim 1 in which the titanium is in theform of a -20 +325 mesh powder.

11. A process in accordance with claim 10 in which the titanium powderhas a particle size of no more than 3 X 10 inch.

12. A process in accordance with claim 1 in which the titanium is atleast partially consolidated titanium powder.

13. A process in. accordance with claim 1 in which the titanium is inthe form of solid cast or wrought titanium metal.

14. A process in accordance with claim 1 in which the titanium materialis titanium alloy.

15. A process in accordance with claim 14 in which the titanium alloy isTi-6Al-4V alloy.

16. A process in accordance with claim 14 in which the titanium alloy isa Ti-5Al-2.5Sn alloy.

17. A process in accordance with claim 1 which also includes the step ofdegassing the extrusion canister to less than 10 microns of mercury.

18. A process in accordance with claim 1 which includes the step ofisopressing the extrudable assembly at a pressure of 30 ksi prior toextrusion.

19. A process in accordance with claim 1 in which the extrusion canisteris formed of low carbon steel.

20. A process in accordance with claim 1 in which the volume percent ofberyllium is from 40% to 60%,

and the balance is titanium or titanium alloy.

UNE'EED S'iA'liCS PA'IHNT ()FEPICE filiiii'limCA?T, Oi CURE? ECEiQNPatent NO. 3,821,841 Dated July 2, 1974 lnventofls) :Vernon L. GoodwinIL is certified that error appears in the above-identified patent andthat said Letters Patent are heroby corrected as shown below:

Column 7, line 56, to should be --of Column 8, line 52, r etangu--should be --rectangu- Column 9, last line, Ti 6A1 2Sn should be Ti 6A16V 2Sn,.

Column 10 i 47 (Beo content)" should be --(Be0 content)--.

Column 11, in the table, line 16, "80-100 psi should be --80l00 ksi-;and

line 17, "ll5-l40 psi should be "115-140 ksi-.

Signed and sealed this 18th day of February 1975.

(SEAL? A'ttest:

c. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officerand Trademarks 'UNHED STATES PA'HSNT OFFICE v CEH'llFlC/KT 01*"C()RH1ZC1Y1QN PaLcnt No. '3 82l,84l Dated July 2, 1974 ,lnv fl :VernonL. Goodwin It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 56, to should be --of- Column 8, line 52, "retangu shouldbe -rectangu Column 9, last line, "Ti 6A1 ZSn should be -Ti 6A1 6V ZSn Cl 10 li 47 (Beo content)" should be --(Be0 content)-.

Column 11, in the table, line 16, 80-100 psi" should be --80-100 ksi-;and

' line 17, "115-140 psi" should be l15-140 ksi-.

Signed and sealed this 18th day of February 1975.

(SEAL? Attest:

C. MARSHALL DANN RUTH c MASON Commissioner of Patents Attestlng Officerand Trademarks

2. A process in accordance with claim 1 which also includes the step ofprestressing the extruded composite.
 2. filling the balance of theassembly with titanium to form a continuous titanium matrix surroundingsaid bodies; b. encasing said assembly in an extrusion canister; and c.extruding said canister at a temperature of from 1,400* to 1, 525*F. ata reduction ratio of from 6:1 to 100:1 to form a solid fibrousberyllium/titanium composite.
 3. A process in accordance with claim 1 inwhich the beryllium fiber precursor is formed from beryllium powderhaving a particle size no greater than 3 X 10 2 inch.
 4. A process inaccordance with claim 1 in which the beryllium has a beryllium oxidecontent of from 0.2% to 6% by weight.
 5. A process in accordance withclaim 1 in which the beryllium fiber precursors are composed of vacuumhot pressed beryllium.
 6. A process in accordance with claim 1 in whichthe beryllium fiber precursors are composed of cold pressed berylliumpowder.
 7. A process in accordance with claim 1 in which the berylliumfiber precursors are composed of cold pressed and sintered berylliumpowder.
 8. A process in accordance with claim 1 in which the berylliumfiber precursors are composed of cold pressed, sintered and coinedberyllium powder.
 9. A process iN accordance with claim 1 in which theberyllium fiber precursors are composed of beryllium powder rigidizedwith a binder.
 10. A process in accordance with claim 1 in which thetitanium is in the form of a -20 +325 mesh powder.
 11. A process inaccordance with claim 10 in which the titanium powder has a particlesize of no more than 3 X 10 2 inch.
 12. A process in accordance withclaim 1 in which the titanium is at least partially consolidatedtitanium powder.
 13. A process in accordance with claim 1 in which thetitanium is in the form of solid cast or wrought titanium metal.
 14. Aprocess in accordance with claim 1 in which the titanium material istitanium alloy.
 15. A process in accordance with claim 14 in which thetitanium alloy is Ti-6Al-4V alloy.
 16. A process in accordance withclaim 14 in which the titanium alloy is a Ti-5Al-2.5Sn alloy.
 17. Aprocess in accordance with claim 1 which also includes the step ofdegassing the extrusion canister to less than 10 microns of mercury. 18.A process in accordance with claim 1 which includes the step ofisopressing the extrudable assembly at a pressure of 30 ksi prior toextrusion.
 19. A process in accordance with claim 1 in which theextrusion canister is formed of low carbon steel.
 20. A process inaccordance with claim 1 in which the volume percent of beryllium is from40% to 60%, and the balance is titanium or titanium alloy.